package dao.impl;

import dao.UserDao;
import pojo.User;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class UserDaoImpl implements UserDao {

    @Override
    public List<User> findAll() {
        List<User> list = new ArrayList<>();

        Connection root = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        //jdbc步骤
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            root = DriverManager.getConnection(url, "root", "2005");
           /* if(root!=null){
                System.out.println("连接成功");
            }*/

            //3.写sql
            String sql = "SELECT * FROM user";
            //4.预编译sql
            preparedStatement = root.prepareStatement(sql);
            //5.执行sql
            resultSet = preparedStatement.executeQuery();
            //6.遍历结果
            while (resultSet.next()) {
                User user = new User();
                user.setId(resultSet.getInt("id"));
                user.setName(resultSet.getString("name"));
                user.setPass(resultSet.getString("pass"));
                list.add(user);
            }
            return list;

        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
            //7.关闭资源  最后创建的最先关闭

            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (root != null) {
                    root.close();
                }

            } catch (SQLException e) {
                throw new RuntimeException(e);
            }


        }
    }

}

